640431296 has 28 divisors (see below), whose sum is σ = 1274905248. Its totient is φ = 319195392.

The previous prime is 640431221. The next prime is 640431299. The reversal of 640431296 is 692134046.

It is a hoax number, since the sum of its digits (35) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (640431299) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4505 + ... + 36071.

Almost surely, 2^640431296 is an apocalyptic number.

It is an amenable number.

640431296 is a deficient number, since it is larger than the sum of its proper divisors (634473952).

640431296 is a wasteful number, since it uses less digits than its factorization.

640431296 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31896 (or 31886 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 35.

The square root of 640431296 is about 25306.7440813709. The cubic root of 640431296 is about 861.9674156821.

The spelling of 640431296 in words is "six hundred forty million, four hundred thirty-one thousand, two hundred ninety-six".